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Single Photon Emission Computed Tomography (SPECT) and SPECT/CT Hybrid Imaging
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Michael Ljungberg, Kjell Erlandsson
Since the scintillation camera, in its essence, is a 2D imaging system that measures count projection generated by photons emitted from a 3D radionuclide distribution in a 3D object, there is no possibility of resolving the depth information of the distribution from a single projection image. In the past, different projections were measured, in order to account for this limitation, but this approach was really not a sufficient solution. By mounting the scintillation camera head on a gantry that could rotate around the patient, the development of SPECT (Single-Photon Emission Computed Tomography) followed the development of Computed Tomography (CT), since the problem with the depth information for planar X-ray imaging was essentially the same.
Evaluation of the Potential of Microspherical Systems for Regional Therapy in the Tumor-Bearing Liver and Kidney Using Techniques in Nuclear Medicine
Published in Neville Willmott, John Daly, Microspheres and Regional Cancer Therapy, 2020
Jacqueline A. Goldberg, James H. McKillop, Colin S. McArdle
Single photon emission computed tomography (SPECT), by contrast, utilizes standard radiopharmaceuticals and equipment that are generally available. To produce tomographic information from a SPECT study images are acquired from a large number of projections over a wide range of angles. The information from these multiple projections is then integrated by computer programs to produce tomographic images. The process, which is analogous to that employed in CT scanning, is explained in more detail next.
Positron Emission Tomography Imaging Systems And Applications
Published in Bhagwat D. Ahluwalia, Tomographic Methods in Nuclear Medicine: Physical Principles, Instruments, and Clinical Applications, 2020
Positron emission computed tomography uses unique biological tracers. It has the potential for measurement of blood flow and metabolism. For brain studies it is specific for detection of lesions, evaluation of stroke, epilepsy, Huntington's disease, and dementia. Similarly, it provides specific information of tissue viability, degree of injury, and specific biochemical defects as far as myocardial imaging is concerned.
Application of thyroglobulin and anti-thyroglobulin antibody combined with emission computed tomography in the adjuvant diagnosis of differentiated thyroid carcinoma
Published in Annals of Medicine, 2023
Nan Jiang, Benzheng Jiao, Laney Zhang, Jialong Li, Yungeng Li, Chenghe Lin
At present, the pathogenesis of TC has not been thoroughly clarified clinically. After the onset, neck mass, decreased blood calcium, diarrhea, hoarseness, dyspnea and dysphagia are the main clinical presentations, affecting the healthy life of patients [12]. Although DTC carries a favorable prognosis, its clinical and biological behavior is relatively slow, resulting in frequent neck lymph node metastasis at diagnosis or during postoperative follow-up [13]. Therefore, preoperative diagnosis and regular postoperative follow-up are particularly important. Pathological examination, a commonly used diagnostic method for TC, is considered as the "gold standard" for the disease. However, it is risky and traumatic, leading to poor patient tolerance for diagnosis [14]. Among the non-invasive diagnostic modalities, ultrasound [15] is most extensively used for early screening of thyroid diseases. However, due to the occlusion of neck muscle tissue and the limited sensitivity of ultrasound itself, its value in early warning or diagnosis of DTC recurrence and metastasis is not high. In recent years, the role of emission computed tomography (ECT) technology in the diagnosis of TC has gradually attracted widespread clinical attention. It is an examination method using radionuclides that, after computer processing, can image the difference in radioactivity concentration between the lesion and normal tissue, providing valuable imaging information for disease diagnosis [16,17].
Gastrin-releasing peptide receptor agonists and antagonists for molecular imaging of breast and prostate cancer: from pre-clinical studies to translational perspectives
Published in Expert Review of Molecular Diagnostics, 2022
Joana Gorica, Maria Silvia De Feo, Luca Filippi, Viviana Frantellizzi, Orazio Schillaci, Giuseppe De Vincentis
The main objective of nuclear medicine is to investigate and gauge metabolic and molecular changes during pathological processes in living subjects through the administration of radiolabeled molecules as imaging probes [19]. Once the radiolabeled probe (i.e. radiopharmaceutical) has been administered, photons produced in the process of radioactive decay and interaction with neighboring tissues are detected by employing appropriate technologies. In the case of gamma-emitting radiopharmaceuticals, such as 99mTc or 111In, imaging is performed by employing the gamma-camera, also through single-photon emission tomography (SPECT) or SPECT/CT hybrid devices [20,21]. When positron-emitting radiopharmaceuticals are utilized, such as 18F or 68Ga, positron emission computed tomography (PET/CT), characterized by superior sensitivity and spatial resolution than SPECT or SPECT/CT, is applied. The use of GRPR analogs for the molecular imaging of prostate cancer patients has provided promising preliminary results. Various bombesin analogs have been labeled with different radioisotopes (64Cu, 18F, 68Ga, 66Ga). GRPR antagonists replaced agonists because of their more favorable pharmacokinetics; they block the receptor instead of activating it (as agonists do), resulting in no gastrointestinal side effects and increased binding [22].
Potential application of mass spectrometry imaging in pharmacokinetic studies
Published in Xenobiotica, 2022
Chukwunonso K. Nwabufo, Omozojie P. Aigbogun
Several molecular imaging platforms that can be used to visualise and quantify drugs at disease target tissues are available, but each has its disadvantages as previously described (Willmann et al. 2008). Optical imaging has limited clinical translation, low depth of penetration, and the probes utilised (e.g. fluorescent probe) could affect the drug PK profile. Magnetic resonance imaging (MRI) is costly and has a high imaging time while imaging using ultrasound technique is limited to the vasculature. Other sophisticated imaging modalities such as positron emission tomography and single-photon-emission computed tomography are limited by the high cost and low spatial resolution (Nwabufo and Aigbogun 2022). On the other hand, computed tomography lacks target specificity and has low soft-tissue contrast. Similarly, autoradiography is costly, has a long imaging time, and suffers from specificity issues due to challenges with distinguishing the radioactivity coming from parent compound and their associated degradation products or metabolites (Spruill et al. 2022). Given that many of these molecular imaging techniques including positron-emission tomography and single-photon-emission computed tomography require the use of radioactive isotopes, it is prone to numerous health and environmental hazards.